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Joachim Wiberg
c584795202
Reference sections kept pointing at the line-based format they no longer
document. `sysv` and `task` sent the reader to Services for "<COND>",
the cgroups chapter opened by listing three legacy directives and then
explained further down that only two of them exist here, and the logging
chapter still gave "log:prio:facility.level,tag:ident" as the full
syntax.
Some claims were wrong independent of the format:
- a sysv is a supervised daemon, grouped with service in
SVC_TYPE_DAEMON, not a variation on task
- restart-max has no upper bound of 255, or any other
- the built-in rescue fallback runs in 12345789, not 12345
- conditional loading quotes system/10-hotplug.conf, not
system/hotplug.conf
- the key spells conflicts, not conflict
- the built-in getty no longer wants TERM last, it is a key
`if` takes either a service name or, in angle brackets, a condition,
decided in svc_ifthen(). Only the examples showed this, so it is now
said.
Terminology follows the split index.md already draws: a block is the new
format, a stanza the line-based one.
src/rescue.conf was still line-based, missed because it sits in src/
rather than system/ or contrib/.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
83 lines
2.8 KiB
Markdown
83 lines
2.8 KiB
Markdown
General Logging
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===============
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**Syntax:** `log { size = 200k count = 5 }`
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Log rotation for run/task/services that redirect output to a log file
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with their own `log` block. Global setting, applies to all services.
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The size can be given as bytes, without a specifier, or in `k`, `M`,
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or `G`, e.g. `size = 10M`, or `size = 3G`. A value of `size = 0` disables
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log rotation. The default is `200k`.
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The count value is recommended to be between 1-5, with a default 5.
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Setting count to 0 means the logfile will be truncated when the MAX
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size limit is reached.
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Redirecting Output
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------------------
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The `run`, `task`, and `service` blocks take a `log` block of their own,
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redirecting `stderr` and `stdout` of the application to a file or syslog
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using the native `logit` tool. This is useful for programs that do not
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support syslog on their own, which is sometimes the case when running
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in the foreground.
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An empty block means syslog with the defaults, and three keys adjust it:
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| Setting | Description |
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|---|---|
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| `file` | Write to this path instead of syslog |
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| `priority` | Syslog `facility.level`, default `daemon.info` |
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| `identity` | Syslog tag, default the basename of the command |
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`/dev/console` and `/dev/null` are spelled as the paths they are:
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service foo { log { } command = "foo" } # syslog
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service foo { log { file = "/var/log/foo" } command = "foo" } # a file
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service foo { log { file = "/dev/console" } command = "foo" } # console
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service foo { log { file = "/dev/null" } command = "foo" } # discard
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> [!NOTE]
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> A `log` block at file scope is a different setting -- that one is the
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> global rotation above, and it takes only `size` and `count`.
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Log rotation is controlled using the global `log` setting.
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**Example:**
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service ntpd {
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description = "NTP daemon"
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log {
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priority = "user.warn"
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identity = "ntpd"
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}
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command = "/sbin/ntpd pool.ntp.org"
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}
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Output Buffering
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----------------
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When using the `log` block, Finit redirects the service's stdout and
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stderr to a pipe connected to a logger process. Programs detect this as
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non-interactive output (i.e., `isatty()` returns false) and typically
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switch from line-buffered to fully-buffered mode.
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Most well-behaved daemons explicitly flush their output or use syslog
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directly, so this is rarely an issue. However, if a service's log
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messages appear delayed or batched, you can force line-buffered output
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by wrapping the command with `stdbuf`:
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service myservice {
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description = "My service"
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log { }
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command = "/usr/bin/stdbuf -oL /path/to/command"
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}
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The `-oL` option forces line-buffered output, and `-o0` forces unbuffered
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output. See `stdbuf(1)` for details.
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> [!NOTE]
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> Using `stdbuf` is rarely necessary. Only use it if you observe actual
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> buffering issues with a specific service.
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